Carroting process



Patented Aug. 13, 1940 UNITED I smrt;

ea'ru'r CARROTING PROCESS New York No Drawing. Application December 1,1937,

Serial No. 177,479 1 8 Claims.

This invention relates to a carroting process, an art of impartingproper felting characteristics to fur fibers.

This application is a continuation in part of 5 my copendingapplications Serial No. 606,525, filed April 20, 1932, and Serial No.104,706, filed October 8, 1936.

One of the objects of this invention is to provide a carroting processwhich will impart one or more of the following'characteristics to furfibers so treated:strong mutual adherence in the resultant fur to maketight felt; fast shrinking and quick starting during the feltingprocess; little or no staining of the fur fibers; no deterioration forsubstantial periods of storage, in fact, improvement during this period;an ability to mix with an unusually large amount of filler in theresultant felt without detracting from the quality of the felt; anability to take all shades of dyes, both light and dark, withoutobjectionable undercasts or mottled effects. Another object of thisinvention is to provide a carroting process utilizing a non-toxic andinexpensive carroting solution. Other objects will be in part 25 obviousand in part pointed out hereinafter.

The invention contemplates the utilization of novel combinations ofchemical reagents for the treatment of furs as will be illustrativelydescribed herein, and the scope of the invention will be indicated inthe following claims.

Generally speaking, felt such as that used in hats comprises a compactmass of interlocking fur fibers. For example, in hat manufacture thefibers are deposited loosely upon a. cone, and after wetting andhardening they cling together to form a body which may be removed andput through various operations to bring it down to the normal size of ahat. These operations may be generally characterized as shrinking,rubbing and pounding under a variety of conditions and with varioustypes of machines, all to assure a rapid achievement of the proper sizeand proper shape. Two of the most important operations are known asstarting and sizing in the batting industry. Fur fibers which have quickstarting and fast shrinking characteristics are naturally desirable inhat manufacture.

Fur fibers in their natural condition on pelts are not suitable forfelting. They must be properly processed prior to the felting operationand this process is generally known in the art as carroting. Thecarroting process is particularly important in the manufacture of feltfor proper felting characteristics are only obtained thereby regardlessof the quality of the fur fibers.

The carroting process usually comprises combing the carroting solutioninto the furwhile-still on the pelt. After drying, the fur is cut fromthe pelt and generally stored for future use in the felting operation.

The desirable carroting solution should have several inherentcharacteristics and should impart to the fur several qualities to makeit commercially desirable. In the first place, the solution should benon-toxic, if possible, to avoid 10 injury not only to the laborersapplying the solution during the carroting process but also the laborersworking in the felting operation. Naturally it is desirable to have aninexpensive carroting solution thus to reduce the ultimate manufacturingcost of the felt. Due to the fact that the fur after carroting mustoften be stored for substantial periods of time before use, the carrotedfur must not deteriorate with time. After the felting operation,especially in the batting industry, the fur must be died. Accordingly,the carroted fur should be able to take all shades of dyes without anyundesirable undercasting or mottled effects. Accordingly to itscharacteristics, the carroting solution materially affects 5 the speedof starting and sizing as referred to above. Naturally a quick startingand fast sizing felt is desirable in order to speed the feltingoperation and thus reduce manufacturing costs. The carroting processshould impart other characteristics to the fur some of which will bercferred to hereinafter.

It is now generally recognized that acarroting solution should include ahydrolyzing agent and an oxidizing agent. Just why these ingredients arenecessary constituents in a carroting solution -is not definitely knownbut successful carroting solutions now in use include these ingredientsin one form or another.

For many years the so-called mercury car- 40 rot was the acceptedstandard carroting solution in the hatting indusry. Mercury carrotcomprises mercury nitrate in an excess of nitric acid and it impartsseveral very desirable characteristics to the fur fibers. Fur socarroted improves with age and thus may be stored for substantialperiods of time. Mercury carrot also seems to add a substantial amountof weight to the fur and fur so carroted is capable of taking a largeamount of filler in the resultant felt. In spite of these advantages themercury carrot is far from ideal. It has a definitely toxic effect whichoften seriously impairs the health of the laborers coming in contactwith fur so carroted.

It discolors the fur, making the use of lighter pastel dye shadesimpossible. and it is expensive.

Because of the shortcomings of the mercury carrot a great deal of efforthas been expended, in an attempt to devise'a non-toxic carrot,preferably non-mercury, due to the above efiects of this element. Thisunusual activity has met with a fair degree of success in some cases andseveral non-mercury carrots have been devised which can be used withsuccess in limited fields. Significantly, however, most of the fur usedin felt manufacture is still carroted with the mercury carrot. In spiteof its toxic effect and other disadvantages, it is still considered bymany to be usually superior to the non-mercury carrots so far developed.

The principal object of this invention has been to devise a practicaland inexpensive carrot retaining in so far as possible all of theadvantages of the mercury carrot while eliminating the importantdisadvantages thereof.

If the mercury carrot is used in dilute solutions the toxic eifectthereof is eliminated for all practical purposes. However, a weaksolution of the mercury carrot has not the strength to impart properfelting characteristics to the fur. I have discovered that thisdeficiency may be eliminated by the addition of two strong oxidizingagents to a Weak mercury carrot solution. To the weak solution ofmercury carrot comprising mercury nitrate in an excess of nitric acid, Iadd strong hydrogen peroxide and any one of several peroxygen compounds.The four peroxygen compounds which I have found workable in thissolution are ammonium persulphate, ammonium perchlorate, sodiumperchlorate and perchloric acid. Of these I have obtained best resultswith ammonium persulphate and accordingly my preferred carrot comprisesmercury nitrate, nitric acid, ammonium persulphate and strong hydrogenperoxide. Different strengths of hydrogen peroxide may be used withvarying results but my present experiments indicate a lower limit of 25volume strength and an upper limit of '75 volume strength although I donot wish to be definitely limited to any particular values. The bestvalues and proportions of the various ingredients comprising thiscarroting solution cannot be exactly stated without several yearsresearch covering a variety of conditions under which the fur is used infelt manufacture. However, good carroting results have been obtained inthe solutions to follow, it being understood that these are merelyillustrative examples and may vary widely in accordance with particularconditions and in accordance with the results obtained from an extendedperiodof use:

Example 1 Mercury nitrate .03 molal Nitric acid .09 molal Ammoniumpersulphate .35 molal Hydrogen peroxide 25 volume strength Example 2Mercury nitrate .04 molal Nitric acid .14 molal Sodium perchlorate .44molal Hydrogen peroxide 45 volume strength Example 3 Mercury nitrate .05molal Nitric acid .15 molal Ammonium perchlorate .35 molal Hydrogenperoxide 45 volume strength Example 4 Mercury nitrate .05 molal Nitricacid .14 molal Perchloric acid .3 molal Hydrogen peroxide 45 volumestrength The above solutions may be applied to the fur by combing beforethe fur has been removed from the pelts without any danger mainlybecause of the small amount of mercury nitrate therein. Furthermore, furso carroted may be used with safety during the felting process withouttoxic effects. The ingredients of the above solutions are relativelyinexpensive thus reducing materially the cost of the carroting process.

Furthermore, I have found that fur carroted in the above describedmanner is unstained and thus may take any shade of dye withoutobjectionable undercasts or mottllng. The fur may be stored for asubstantial period of time and improves with age; the solution also addsconsiderable weight to the fur in the same manner as previouslyexplained with respect to the mercury carrot. Such fur is also quickstarting and fast shrinking, characteristics much to be desired by thehat manufacturer. Further still, this fur is capable of taking asubstantial quantity of filler in the felt without deteriorationthereof. Briefly, fur carroted with the above solutions retains the manyadvantages of the mercury carrot without the disadvantages and at aconsiderable saving in expense,

Accordingly, it will be seen that the several objects hereinabovereferrd to as well as many others have been successfully and practicallyaccomplished.

As the art herein described may be varied in various parts withoutdeparting from the scope of the invention, it is to be understood thatall matter hereinbefore set forth is to be interpreted as illustrativeand not in a limiting sense.

I claim: I

l. The herein described art of preparing fur for felting comprisingapplying to the fur a solution of mercury nitrate containing an excessof nitric acid, hydrogen peroxide, and a substance selected from thegroup consisting of ammonium persulphate, sodium perchlorate, ammoniumperchlorate, and perchloric acid.

2. The herein described art of preparing fur for felting comprisingapplying to the fur a solution of mercury nitrate containing an excessof nitric acid, hydrogen peroxide of between 25 and volume strength, anda substance selected from the group consisting of ammonium persulphate,sodium perchlorate, ammonium perchlorate, and perchloric acid.

3. The herein described art of preparing fur for felting comprisingapplying to the fur a solution of mercury nitrate containing an excessof nitric acid, hydrogen peroxide, and ammonium persulphate.

4. The herein described art of preparing fur for felting comprisingapplying to the fur a solution of mercury nitrate containing an excessof nitric acid, hydrogen peroxide, and sodium perchlorate.

5. The herein described art of preparing fur for felting comprisingapplying to the fur a solution of mercury nitrate containing an excessof nitric acid, hydrogen peroxide, and ammonium perchlorate.

6. The herein described art of preparing fur for felting comprisingapplying to the fur a solution of mercury nitrate .03 molal, nitric acid.09

8. The herein described art of preparing fur for felting comprisingapplying to the fur a solution of mercury nitrate .05 molal, nitric acid.15 molal, ammonium perchlorate .35 moial, and hydrogen peroxide of 45volume strength.

' WARREN c. MERCIER.

